An example 8×8 Sudoku: digits 1-8 fill every row, column and 2×4 box.
8×8 Sudoku is an eight-by-eight grid using the digits 1-8, divided into 2×4 boxes - two cells tall and four wide. Each row, column and box must hold every digit once. It sits neatly between the gentle 6×6 and the full 9×9: bigger than a beginner grid, but still quick and forgiving.
The rule: 1-8 in every row, column and 2×4 box
Fill the grid so no digit repeats in any row, any column or any 2×4 box. The rectangular boxes - four wide, two tall - are the only structural change from Classic Sudoku. Here is a completed 8×8 grid.
A finished 8×8 grid: every row, column and 2×4 box holds 1-8 once.
Rectangular boxes shift the balance
A 2×4 box spans four columns but only two rows, so it interacts with columns and rows unevenly. A digit placed in a box clears it from four columns' worth of that box but only two rows' worth - so, as in the 6×6, column scanning tends to be a little more powerful than row scanning. Some 8×8 puzzles use 4×2 boxes (four tall, two wide) instead; the logic is identical, just rotated.
A comfortable middle size
With 64 cells and eight digits, an 8×8 is roomy enough to need real technique yet small enough to finish in a sitting. Every method from the 9×9 works here in miniature: scan a unit for a missing digit, look for a cell with only one option, and pencil candidates where a box or line is nearly full. It is an ideal grid for a solver who has outgrown the 6×6 but isn't yet reaching for Expert 9×9s.
Solving strategy
- Scan columns first. The wide 2×4 boxes make column eliminations especially effective.
- Complete near-full units. A row, column or box with seven of its eight digits gives the eighth for free.
- Hunt hidden singles. With eight cells per box, a digit is often confined to a single empty cell quickly.
- Pencil the pairs. Naked and hidden pairs still apply and resolve fast on the smaller grid.
Common mistakes
- Expecting square boxes. The boxes are 2×4 rectangles - check the printed borders before reasoning about a box.
- Using a 9. Only the digits 1-8 appear on an 8×8 grid.
- Forgetting a rule. Rows, columns and boxes all still apply, exactly as on the full grid.
- Underrating it. A hard 8×8 can still demand genuine deduction - small does not mean trivial.
Can I play it here?
Not yet - Sudoku 8×8 isn't one of the puzzle types SudokuStreak generates for now. But you can learn its rules above, and there's plenty here to sink your teeth into meanwhile:
- Try the closely related Classic, which you can play right now.
- Browse all the Sudoku variants we do offer.
- Or print free puzzles from the printable PDF page.
Where to play it
Sudoku 8×8 belongs to the size variant family and runs on 8×8. It is not one SudokuStreak generates yet - but the deduction it trains is the deduction every Sudoku runs on.
Difficulty and type are two separate dials here: the type sets the extra rule, the level sets how much of the grid you start with. Expert Sudoku leaves 25 of the 81 cells filled, where the beginner tools dry up almost entirely; Evil Sudoku leaves 23, with no easy moves at all. Take it at the gentler end while the pattern is still new, and move up once it stops being a fight.